"Christopher Spence" <nospam_at_cspence@delphi-tech.com> wrote in message
news:38bd39de$0$3481_at_wodc7nh0.news.uu.net...
> Anyone have any experience with problems with CBO in 7.3.x?
>
> Full schema Analyze, 25% Estimate Statistics
> 3 days later
> 3 tables join queried with hint /*+ rule */
> Results: 240ms
> 3 tables join queried with no hints (use CBO as there is statistics)
> Results: 2300ms
> Manually Analyze the 3 tables
> 3 tables join queried with no hints (use CBO as there is statistics)
> Results: 220ms
>
Looks to me from these results that the sample was not representative and
analyze table compute statistics would be a better bet. Alternatively move
back to RBO. In particular it looks like your sample does a poor job of
estimating the cardinality of the appropriate indexes.
Received on Thu Mar 02 2000 - 00:00:00 CST
